Matlabcommand_s parameter to transmission line parameters conversion

I have used the matlab command

's2t'

However when i computed these parameters on my own using the following formulas as available in various books i found a discrepancy. The resultant t-params are in the wrong order. Can someone plz help?

I am expalining the matter with the following examples:

the s-matrix is given below:

S= -0.5160 + 0.1537i 0.0859 + 0.2458i 0.0803 + 0.2368i 0.2874 + 0.6638i

using the s2t command i got the following t-params:

T= 1.2843 - 3.7874i -2.8832 + 0.2360i -0.0806 + 2.1517i 1.5374 - 0.3191i

however when i computed it using the formulas given in books the s-parameters computed are:

T1= 1.5374 - 0.3191i -0.0806 + 2.1517i -2.8832 + 0.2360i 1.2843 - 3.7874i

Formulas used are:

T11=-(det(s_params))/s_21 T12=s_11/s_21 T21=-s_22/s_21 T22=1/s_21

plz note tht the orders are reversed(e.g S11 becomes S22 etc). Has anyone encountered this problem before?

Answer 1

[Ge Davidson]

Formulas

t11 = 1/s21;

t12 = -(1/s21)*s22;

t21 = s11*(1/s21);

t22 = s12-s11*(1/s21)*s22;